CVE-2019-13115 — In libssh2 before 1

In libssh2 before 1.9.0, kex_method_diffie_hellman_group_exchange_sha256_key_exchange in kex.c has an integer overflow that could lead to an out-of-bounds read in the way packets are read from the server. A remote attacker who compromises a SSH server may be able to disclose sens

01What is this vulnerability?

In libssh2 before 1.9.0, kex_method_diffie_hellman_group_exchange_sha256_key_exchange in kex.c has an integer overflow that could lead to an out-of-bounds read in the way packets are read from the server. A remote attacker who compromises a SSH server may be able to disclose sensitive information or cause a denial of service condition on the client system when a user connects to the server. This…

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-07-16T00:00:00.000Z
• Last modified: 2024-08-04T23:41:10.457Z

09References

• github.com — https://github.com/libssh2/libssh2/pull/350
• libssh2.org — https://libssh2.org/changes.html
• github.com — https://github.com/libssh2/libssh2/compare/02ecf17...42d37aa
• blog.semmle.com — https://blog.semmle.com/libssh2-integer-overflow/
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2019/07/msg00024.html
• lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro…
• lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro…
• security.netapp.com — https://security.netapp.com/advisory/ntap-20190806-0002/
• support.f5.com — https://support.f5.com/csp/article/K13322484
• support.f5.com — https://support.f5.com/csp/article/K13322484?utm_source=f5support&amp%3Butm_medi…
• lists.apache.org — https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8…
• lists.apache.org — https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e3…
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2021/12/msg00013.html
• packetstormsecurity.com — http://packetstormsecurity.com/files/172834/libssh2-1.8.2-Out-Of-Bounds-Read.htm…
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2023/09/msg00006.html